Apparatus for determining specific gravity



Sept. '7, 1943. D. DAVIDSON EI'AL 87 APPARATUS FOR DETERMINING SPECIFIC GRAVITY Filed March 23, 1940 BY M/L 70 PoPams/rr P/l/l/P imscwamrf IITI'ORNE'Y Patented Sept. 7, 19 13 U IT-so STAT S PAT ENT optics I.

APPARATUS FOR DETERMINING SPECIFIC GRAVITY 1 D-avidDavidson, New York, and Milton Popovvsky 1 and Philip Rosenblatt, Brooklyn, N. Y.

Application March 23, 1940, Serial No. 325,506 -2- Claims. (Cl.'2 65 44) 4 This invention relates to an apparatus for determining the specific gravity of a liquid.

- For this purpose there have beenused heretofore many different kinds of apparatus and methods. M

In one method considered 'only approximate in the results obtained, there have been used two partly filled U-tubes containing. two liquids. The tubes stand substantially vertically and have. a side of each tube connected to the otherand to means for applying suction or pressure. The other side of each tube is open to the atmosphere. When the suction or pressure is ap-plied, the liquids in the' connected sides are vraised or depressed to an extent varying inversely with the specific gravities. column of, the liquids in "the twosides of the tubes may then be used to calculate the density of the one liquid in terms of the other. If one liquid is a standard liquid of known specific gravity, then the specific gravity of the other liquid may be calculated, since at equilibrium the hydrostatic pressure due to each liquid will be the same. In using this method, it is necessary to read two positions for each liquid, namely, the positions of the menisci of the liquid in each side of the U-tubes.

With our improved apparatus balanced liquid columns, are used, but the need of reading two elevations for each liquid is eliminated. In fact, when the apparatus has been calibrated as will be described, the only reading to be recorded is one position on a scale graduated in terms of specific gravity.

It is, therefore, an object of the invention -to provide a simplified apparatus for determining the specific gravity of a liquid by comparison with a standard liquid of known specific gravity. Another object is to provide an apparatus by means of which the relative heights of balancing columns of two liquids may be compared with a satisfactory degree of accuracy. These and such other objects as will appear from the description are secured by the apparatus to be disclosed.

The invention comprises the combination, construction, arrangement, and relative location of the parts of the apparatus described herein. The invention more particularly comprises apparatus for determining the specific gravity by elevating a column of a liquid above a portion thereof that is unchanging in its level and comparing the heights of this column and a balancing column of a liquid of known specific gravity.

The invention will be illustrated by descrip- The difference in height of i tion'in connection with the attached drawing to which referenceis made.

The figure is a front elevation of the preferred embodiment of the apparatus andis in part diagrammatic.

There is shown a rigid support Ill for the apparatus that may be of any suitable form or material of construction, as, for example, Wood, metal, or molded plastic with base H and an upright, member l2 firmly secured thereto, as by'screws or other means not shown.

The measuring apparatus proper includes the bent glass tube having a side I3 that extends horizontally, and a side 14 continuous with the horizontalside. The side l 4 extends upwardly at a predetermined angle. from the horizontal,

as, for example, substantially vertically. This bent tube is of capillary bore, say.0.5 to 2 mm. orsomewhat larger, and at oneend is provided to advantage with a funnel-like filling member l5 which is open to the atmosphere. Such tube is adapted, whether lying horizontally or extending vertically, to retain liquid as a continuous column filling the cross section of the tube. The surface tension of the liquid causes the liquid to extend completely across the tube and overcomes the force of gravity tending 'to'cause the liquid to rest in the lower part only of the bore of the tube.

The tube for the standard liquid contains horizontally extendingsides or limbs 16 and I1 disposed one above the other at substantially difierent elevations, with a connecting member l8. These parts may constitute conveniently a Z-type tube. The standard liquid is supplied through 7 end [9. 1

The tubes are joined, as by short lengths 20 and 2i of rubber tubing, to a T-tube 22 provided with stop-cock 23, which in turn is connected to cock is then closed.

A scale 24 is supported directly behind the upwardly extending side I4 of the tube for the un known liquid.

' To calibrate this apparatus points on the scale may be established by the use of two liquids of suction sufiicient to establish the menisci of the standard liquid in parts I! and [6. The. position of the meniscus of the unknown liquid on scale 24 is then read as the specific gravity of, the said liquid.

Alternately, the standard liquid may be 'contained in parts 13 and I4 and the liquid of unknown specific gravity in the Z-tube of parts I6, I! and Hi. In this case, the scale 'islin'ear and is established in usual manner, by means of two liquids of known specific gravities, as de scribed above. c

- It will be understood that the terms bent tube and tubularvmember are used herein to include not only integral tubes of glass or the like, but-also assemblies in which separate pieces of tubing arejoined, as by rubber tubing.

'It will be understood also that the details given are for the purpose of illustration; not restriction, and that variations within the spirit of the invention are intended to'be included in the scope of the appended claims."

What we claim is:

1. An apparatusfor measuring the density of i a liquid of unknown specific gravity which comprises a tube for containing the 'unknown liquid,

said tube having a horizontal and avertical portion; a tubular member for receiving a standard liquid, comprising two horizontal end portions disposed at substantially difierent elevations and a tubular connection therebetween; a second tubular member extending between the top of the said vertical tube and the upper one of the said end portions; means in communication with said second member and connectable with a source of partial vacuum for causing a,

'nati'ng at its two ends in the said end portions tubular member:

of the tubular member.

2. An apparatus for measuring the density of I a liquid of unknown specific gravity by balancing a column of it against a column of a standard liquid of known specific gravity, the apparatus comprising a tube for containing one of the liquids, said tube having a horizontal and a vertical portion; atubular member for receiving the other of the liquids comprising two hori- -zontal end portions disposed at substantially different elevations and a tubular connection therebetween; a second tubular member extend- 'i'ng between the top of the said vertical portion of the'tube and the upper one or the said end portions; means in communication with said second memberfiandconne'ctable' with a source of partial vacuum for causing a-portion of the said one of the liquids to rise in the vertical tube;

and means for reading the height 'of the column thus established when balanced against a column of the said other of the liquids terminating at itsftwo'e'nds in the said end'po'rtion's of the DAVID DAVIDSON; NHLTON POPOWSKYI PHILIP ROSENBLA'LI'I'. 

